Re: [gtk-osx-users] Pasting images from clipboard

[John Ralls <jralls ceridwen us>]

> On Feb 9, 2016, at 2:27 AM, Miroslav Rajcic <mrajcic hotmail com> wrote:
>
> Is pasting images from the clipboard supported in GTK 2.x for OS X?
> In my app, the same code doesn't work on OS X but works OK on all other platforms (Windows, Linux, BSD, 
> ...).
>
> Actual code goes like this:
>
> - paste is initialized by call to:
>     GtkClipboard *clipboard = gtk_widget_get_clipboard (g_text.m_pWidget, GDK_SELECTION_CLIPBOARD);
>     gtk_clipboard_request_targets(clipboard, OnPasteClipboardTargetsReceivedFunc, NULL);
>
> - inside OnPasteClipboardTargetsReceivedFunc callback, I do actual pasting with:
>     if(gtk_targets_include_image(atoms, n_atoms, FALSE)){
>         GtkPixbuf *pixbuf = gtk_clipboard_wait_for_image(clipboard);
>         if(!pixbuf){
>             gtkMessageBox(_("Failed to open image from the clipboard!"));
>         }
>    }
>
> This GTK API call fails consistently all the time (returning NULL) on OS X (triggering error message box 
> below).
> Is this a known issue?
>
> Note that pasting works OK for other types of content (text, RTF), but naturally I use different calls to 
> fetch those.
> The app is bundled with all image loaders, inserting image from file works OK, only clipboard operation is 
> problematic.

How are you putting the image into the clipboard and what kind of image is it? The quartz clipboard functions 
are implemented separately from the other platforms in gtkclipboard-quartz.c:

gtk_clipboard_wait_for_image (GtkClipboard *clipboard)
{
  const gchar *priority[] = { "image/png", "image/tiff", "image/jpeg", "image/gif", "image/bmp" };
  int i;
  GtkSelectionData *data;

  for (i = 0; i < G_N_ELEMENTS (priority); i++)
    {
      data = gtk_clipboard_wait_for_contents (clipboard, gdk_atom_intern_static_string (priority[i]));

      if (data)
        {
          GdkPixbuf *pixbuf = gtk_selection_data_get_pixbuf (data);

          gtk_selection_data_free (data);

          return pixbuf;
        }
  }

  return NULL;
}

Note that it will only handle the 5 image types in the "priority" array. 

Regards,
John Ralls